CN101621362B - Method for improving utilization rate of wireless personal network channel - Google Patents

Abstract

The invention discloses a method for improving utilization rate of a wireless personal network channel. The method comprises a step of adjusting a data transmission ACK mechanism, adopts a No-ACK mechanism when the bit error rate of the channel is less than or equal to 1e-5, and adopts an Imm-ACK or Dly-ACK mechanism when the bit error rate of the channel is more than or equal to 1e-3. The method can further reduce the transmission of control information so as to improve the utilization rate of the channel.

Description

Improve the method for utilization rate of wireless personal network channel

Technical field

The invention belongs to communication information technical field, relate to a kind of data transmission method of private wireless network, relate in particular to a kind of method that improves utilization rate of wireless personal network channel.

Background technology

The fading characteristic that the time-varying characteristics of radio communication channel and multipath transmisstion cause makes Frame usually have higher bit error rate in transmission course, thereby causes the low of data frame transfer efficient and channel utilization.How to improve the channel utilization in the wireless personal network, naturally become current and problem in the urgent need to address in wireless communication field from now on.For the raising of channel transport efficiency, the scheme that proposes in current agreement and the document comprises: 1) adopt suitable ACK (Acknowledgement) mechanism; 2) adopt suitable link circuit self-adapting mode; 3) adopt suitable retransmission scheme.Be summarized as follows respectively:

1) adopts suitable ACK (Acknowledgement) mechanism

Having stipulated the ACK mechanism of three kinds of transfer of data in high speed wireless personal network network agreement IEEE 802.15.3, is respectively 1) No-ACK; 2) Imm-ACK (Immediate-ACK); 3) Dly-ACK (Delayed-ACK).Main executive mode and the characteristics of these three or three kinds of ACK mechanism are as follows:

(1) No-ACK is under this ACK mechanism, no matter the Frame correctness that receives, receiving node is not to the sending node feedback information, so No-ACK mechanism does not guarantee the transmission quality of Frame at the MAC layer.Yet No-ACK mechanism can be saved a lot of redundancy overhead in the extraordinary situation of channel conditions, switches the required time etc. between transmission state and accepting state such as transmission time, the sending node of ACK frame, thereby improves systematic function.

(2) Imm-ACK is under this ACK mechanism, sending node is waited for the feedback information of receiving node after transferring frame data, if receiving node correctly receives data, then to sending node feeding back ACK frame acknowledgment, if the data of receiving are wrong, then can not feed back any information to sending node; For sending node, if receive the ACK frame, then transmit the next frame data, if do not receive the ACK frame after wait for a period of time (ACK timeout), then retransmit this frame data.When the number of times of Frame re-transmission surpasses the maximum retransmission restriction, sending node will abandon these frame data, transmit new Frame.

(3) Dly-ACK this be for the custom-designed a kind of ACK mechanism of high speed wireless personal network network, its basic thought is (to be called a brust) after sending node transfers a plurality of Frames continuously, send again an ACK claim frame (ACK Request) or in the last frame data of Burst the information of identification request ACK frame, wait for that then receiving node is to the feedback acknowledgment information of these Frames.Receiving node can feed back an ACK frame after obtaining the ACK solicited message, this ACK frame will transmit correct Frame to all to be confirmed; After sending node is received the Dly-ACK frame, will in next Burst, retransmit by the Frame to error of transmission.Equally, if the number of times that retransmits surpasses the maximum retransmission restriction, sending node will abandon these frame data, transmits new Frame.

Transfer of data normally adopts the fixing Frame length of specific ACK mechanism combination to carry out in the existing cordless communication network, and the defective of this transmission means is:

A, do not consider ACK mechanism to the adaptability of channel variation, namely after receiving terminal obtained channel condition information, the optimum ACK mechanism among the How to choose IEEE 802.15.3 was carried out transfer of data.Consider the impact of different retransmission schemes, the selection of optimum ACK mechanism just need to be in conjunction with factors such as Frame length, transmission rate and re-transmission gains.

B, do not consider that Frame length is on the impact of channel utilization.Because time variation and the frequency selective fading characteristic of wireless channel, if only adopt fixing Frame length that the efficiency of transmission of Frame is reduced greatly, only have in conjunction with the characteristic of channel and dynamically adjust Frame length, the performance of system is improved.

2) adopt suitable link circuit self-adapting mode

The impact of link circuit self-adapting mode:

Link circuit self-adapting can be realized by multiple technologies, such as adaptive coding modulation, self-adapting data frame length adjustment technology, adaptive power control technology etc.Adaptive coding and modulating is present popular technology, also is the effective ways that improve wireless system capacity; Yet obviously not optimum by the adaptive mode of selecting the coded modulation form merely, this is because the length of Frame has vital effect for throughput of system, the frame error rate performance is mainly determined by three factors: channel conditions, code modulation mode and Frame length, and its fundamental relation is as follows:

$\mathrm{FER}\left(\mathrm{\γ}\right)=1-{(1-\mathrm{BER}\left(\mathrm{\γ}\right))}^{L_D}$

Wherein BER (γ) refers to when statistic SINR (SINR) is γ, and physical layer is selected the bit error rate performance behind certain code modulation mode, L _DRefer to selected Frame length.This shows that the data bit that the correct reception of a Frame needs it to comprise all is correctly decoded.If adopt long Frame to transmit, although can save a lot of transmitting redundancies (such as ACK expense, frame period time etc.), but the probability of Frame mistake and Frame length refer to the relation that number increases, therefore long Frame will be more prone in transmission course make mistakes cause re-transmission that this will reduce channel utilization; On the other hand, adopt short Frame to transmit and to guarantee very high transmission correctness, but but need to have introduced a large amount of transmitting redundancies, be unfavorable for equally the raising of channel utilization.Therefore, select suitable Frame length to be used for transmission and seem particularly necessary.For this problem, Legend Company has proposed the dynamic adjusting data frame length in a patent scheme improves the utilance of channel, and its denomination of invention is " a kind of method that improves the radio network information channel efficiency of transmission ".But this patent has following three aspects: not enough:

A, this patent are mainly carried for IEEE 802.11 WLAN (wireless local area network), and have only considered a kind of ACK mechanism, and relate to multiple ACK mechanism in IEEE 802.15.3 agreement, therefore just need to be in optimized selection multiple ACK mechanism.

Therefore B, this patent are not considered the impact of HARQ folding, will be difficult to guarantee system transmissions efficient under abominable channel circumstance, and after the gain that brings in conjunction with the HARQ technology system parameters being optimized to provide better performance.

C, this patent have only been considered to adjust Frame length by the quantity of ACK, and the Frame length that obtains so obviously is not optimum, and this also can increase the waste of radio channel resource.

3) adopt suitable retransmission scheme

The selection of retransmission scheme:

Radio communication channel the time become and the higher error rate that the decline characteristics usually can be brought to transfer of data; in order to guarantee the reliability of transfer of data; ARQ and FEC technology have been widely used in wireless communication system; the ARQ technology is to improve the probability of data frame transfer success by the mode of Frame verification and re-transmission, and the FEC technology is to improve the impact of error of transmission by the mode of chnnel coding.

And be considered to a key technology in the third generation wireless communication system (such as CDMA2000 1xEV, WCDMAHSDPA etc.) and the 3G (Third Generation) Moblie cooperative partner project (3GPP) in conjunction with the HARQ technology of FEC and ARQ, also be considered to simultaneously from now on high-speed radio local area network (LAN) and a basis that the territory net is achieved, it can improve the impact that badly causes of wireless channel to a great extent.HARQ can be divided into following three kinds of schemes:

(1) I type HARQ (Type-I HARQ)

Such HARQ is the simple combination with the function of FEC and ARQ, namely added the CRC sequence at transmitting terminal, then data are through the FEC coding, receiving terminal is tested to transmission correctness with the CRC sequence afterwards in decoding, and with result feedback to transmitting terminal, transmitting terminal retransmits the Frame of mistake.

(2) II type HARQ (Type-II HARQ)

Different from Type-I HARQ is, after adopting Type-II HARQ scheme, receiving terminal is when receiving the Frame of makeing mistakes, do not abandon this Frame, but it is cached, and merge rear decoding with the Frame that retransmits, can take full advantage of like this efficient that useful information in the error data frame improves Frame.Type-II HARQ is called again Chase CombiningHARQ scheme, it is identical with the data frame format of first transmission that transmitting terminal is used for the Frame of re-transmission, and receiving terminal by merging mistake Frame and the Frame of re-transmission increase effective statistic SINR, thereby improve the probability of correct decoding.

(3) III type HARQ (Type-III HARQ)

Type-III HARQ is called again steadily increase redundancy (Incremental Redundancy, IR) HARQ scheme, under this merging mode, the transmission with the re-transmission Frame in can contain different redundant informations, receiving terminal is deciphered by the mode that redundancy merges, can merge gain thereby obtain certain code word so that the code check of transfer of data reduces like this, successfully decoded probability is increased greatly.

Although at present existing a large amount of literature research different ARQ technology, such as (Stop-and-Wait) SW, Go-Back-N (GBN) and Selective Repeat (SR), and all kinds of HARQ technology, yet they all design for the centralized environment of base station.It is pointed out that under this communication environment, all links are all set up between base station and mobile terminal, thereby the base station can directly obtain information such as channel conditions, transmission rate, and then easily realize transmission control.Yet do not have the concept of base station based on the wireless personal network structure of IEEE 802.15.3, the normal operation of whole network is coordinated to carry out by PNC, and PNC does not participate in two communications between the node.Therefore receiving node need to be estimated channel conditions, then selects suitable ACK mechanism and Frame length and feeds back to sending node and PNC.PNC will come to each communication link allocated channel time by broadcasting Beacon frame when next superframe begins.

In sum, because personal network's itself characteristics and applied environment, also there is not so far documents to cross in IEEE 802.15.3 high speed wireless personal network network, in conjunction with the adjustment of the adjustment that how to realize different ACK mechanism behind the performance gain of HARQ and different pieces of information frame length.

Summary of the invention

Technical problem to be solved by this invention is: a kind of method that can improve utilization rate of wireless personal network channel is provided.

For solving the problems of the technologies described above, the present invention adopts following technical scheme:

A kind of method that improves utilization rate of wireless personal network channel, the method comprise the step of adjusting transfer of data ACK mechanism; When the error rate of channel less than or equal to 1e ^-5Shi Caiyong No-ACK mechanism, when the error rate of channel more than or equal to 1e ^-3Shi Caiyong Imm-ACK or Dly-ACK mechanism.

As a preferred embodiment of the present invention, described method also comprises the step of adjusting Frame length; When the error rate of channel less than 1e ^-5More than Shi Zengjia Frame length to 1536 byte, when the error rate of channel greater than 1e ^-3In time, reduce below Frame length to 512 byte.

As a preferred embodiment of the present invention, described private wireless network comprises some sending nodes, some receiving nodes, some PNC; Receiving node is estimated channel conditions, selects optimum ACK mechanism and corresponding optimal transmission Frame length information, and described information is fed back to corresponding sending node and PNC, and described feedback information sends by the form of FEEDBACK CONTROL frame.

As a preferred embodiment of the present invention, the selection of described optimum ACK mechanism, and the selection of optimum frame length obtain by the calculation expression of optimizing throughput; The calculation expression of throughput can obtain by the data transfer model of setting up different ACK mechanism, this be one about the expression formula of Frame length, transmission rate, channel bit error rate, frame period time and ACK length parameter, under different channel bit error rates, obtain corresponding optimum frame length by the method for numerical optimization.

As a preferred embodiment of the present invention, the calculation expression of described throughput is as follows:

Do not consider the transmission error of Beacon frame, data frame header, ACK claim frame and ACK frame, for Imm-ACK and Dly-ACK mechanism, the throughput expression formula is expressed as follows:

$S=\frac{L_D(1-{\mathrm{\Π}}_{k=1}^{N_{\max }+1}\mathrm{FER}\left(k\right))}{T_{\mathrm{slot}}[{\mathrm{\Σ}}_{k=1}^{N_{\max }+1}q(1-\mathrm{FER}\left(k\right)){\mathrm{\Π}}_{q=1}^{k-1}\mathrm{FER}\left(q\right)+(N_{\max }+1){\mathrm{\Π}}_{k=1}^{N_{\max }+1}\mathrm{FER}\left(k\right)]};$

Wherein FER (k) represents the detection frame error rate of Frame receiving terminal when the k time transmission, receiving terminal can merge detection to the Frame that retransmits after adopting the HARQ scheme, therefore FER (k) reduces along with the increase of k, and the length of FER (k) and Frame and the relation of the error rate are as follows: $\mathrm{FER}\left(k\right)=1-{(1-p_e\left(k\right))}^{L_D+L_F};$

When adopting Imm-ACK mechanism, T _SlotCan be expressed as: $T_{\mathrm{slot}}=\frac{L_D+L_F}{R_D}+\frac{L_A+L_H}{R_B}+2T_p+2\mathrm{SIFS};$

When adopting Dly-ACK mechanism (length of supposing Burst is K), T _SlotCan be expressed as:

$T_{\mathrm{slot}}=t_p+\mathrm{MIFS}+\frac{L_D+L_F}{R_D}+\frac{L_H}{R_B}+\frac{1}{K}({2t}_p+2\mathrm{SIFS}+\frac{L_R+L_A}{R_B});$

Wherein MIFS and SIFS are the frame period time that defines in the agreement;

For No-ACK mechanism, the throughput expression formula is as follows: $S=\frac{L_D(1-\mathrm{FER})}{t_p+\mathrm{MIFS}+\frac{L_D+L_F}{R_D}+\frac{L_H}{R_B}}.$

As a preferred embodiment of the present invention, described FEEDBACK CONTROL frame comprises the Frame control part of 2 bytes.

As a preferred embodiment of the present invention, described Frame control partly comprises Framesize level, the ACK policy in order to identify optimum ACK mechanism, the type Frame type that reaches expression FEEDBACK CONTROL frame of the reserved field that utilizes in the agreement.

As a preferred embodiment of the present invention, described method comprises the steps:

Steps A, initial, the ACK mechanism of transfer of data is No-ACK mechanism, Imm-ACK is machine-processed or Dly-ACK mechanism, sending node is first to PNC request channels resource in the contention access period CAP stage, PNC is according to the information of request, for this communication link distributes transmission time slot CTA, reserved the transmission time for the FEEDBACK CONTROL frame among the CTA, and by sending the information of Beacon broadcast channel assigned;

Step B, sending node solve corresponding channel allocation information after receiving Beacon, communication link is based upon in the CTA time slot of appointment, and communication node carries out data transfer according to the ACK mechanism of appointment;

Step C, receiving node estimating channel conditions, and according to the code modulation mode that current link adopts, select best ACK mechanism and Frame length, rear to sending node and PNC transmission FEEDBACK CONTROL frame at the CTA time slot;

Step D, PNC are combined in the information request channel that the CAP of current superframe received in the cycle after receiving the FEEDBACK CONTROL frame, be that this communication link distributes suitable CTA length, when next superframe begins by Beacon broadcast allocation information;

Step e, sending node upgrade the Frame length of ACK mechanism and transmission after receiving the FEEDBACK CONTROL frame, and are combined in the transmission time slot information in the Beacon frame of receiving when next superframe begins, and carry out data communication in the CTA of appointment;

Step F, circulation execution in step C are to step e.

As a preferred embodiment of the present invention, when the error rate of channel greater than 1e ^-5Less than 1e ^-3Shi Caiyong No-ACK mechanism or Imm-ACK or Dly-ACK mechanism.

Beneficial effect of the present invention is:

(1) overhead of introducing about feedback control information.At first, the length of FEEDBACK CONTROL frame only is equivalent to the length of a data frame header; Secondly, the adaptation scheme that the present invention carries is adjusted take superframe as unit, transmission primaries only in each CTA.Therefore, the redundant information introduced of this feedback mechanism is considerably less.

(2) about the applied environment of scheme.Wireless personal network based on IEEE 802.15.3 is mainly used in the home network, than the environment of outdoor mobile communication, the channel conditions impact that is brought by Doppler frequency shift etc. will be little a lot, the variation of channel is slower in general.Therefore the cycle of parameter adjustment can arrange longer (specifically length and the applied environment by superframe determines), can further reduce like this transmission of control information, thereby improve channel utilization.

Description of drawings

Fig. 1 is the composition schematic diagram of FEEDBACK CONTROL frame.

Fig. 2 is basic network framework schematic diagram.

Embodiment

Describe the preferred embodiments of the present invention in detail below in conjunction with accompanying drawing.

The present invention is directed to the performance difference of various ACK mechanism under the different channels environment, propose the scheme of self adaptation ACK mechanism.According to the estimation of receiving node to channel conditions, adjust best transferring ACK mechanism.When channel conditions is better, adopt No-ACK mechanism, by reducing the throughput performance of redundant raising system; When channel conditions is relatively poor, adopt Imm-ACK or Dly-ACK mechanism, and in conjunction with the HARQ Merge Scenarios, both guaranteed the reliability of transfer of data, improved again the channel utilization of system.

A kind of method that improves utilization rate of wireless personal network channel provided by the invention, wherein, private wireless network comprises some sending nodes, some receiving nodes, some PNC (microgrid controller).The method comprises the step of adjusting transfer of data ACK mechanism; When the error rate of channel less than or equal to 1e ^-5Shi Caiyong No-ACK mechanism, when the error rate of channel more than or equal to 1e ^-3Shi Caiyong Imm-ACK or Dly-ACK mechanism.When the error rate of channel greater than 1e ^-5Less than 1e ^-3Shi Caiyong No-ACK mechanism or Imm-ACK or Dly-ACK mechanism.

Simultaneously, the present invention is directed to the transmission of data frame length to the impact of systematic function, propose to adopt optimum Frame length to improve throughput of system at receiving terminal according to channel conditions.Because the selective dependency of optimum ACK mechanism is in Frame length, the selection of optimum frame length adjustment and ACK mechanism combined further to have improved the channel utilization of system.Be specially: when the situation of channel better (such as the error rate less than 1e ^-5) time increase Frame length, as increase to more than 1536 bytes, when the situation of channel relatively poor (such as the error rate greater than 1e ^-3) time reduce Frame length, as be decreased to below 512 bytes.

Receiving node is estimated channel conditions, selects optimum ACK mechanism and corresponding optimal transmission Frame length information, and described information is fed back to corresponding sending node and PNC, and described feedback information sends by the form of FEEDBACK CONTROL frame.The selection of described optimum ACK mechanism, and the selection of optimum frame length obtain by the calculation expression of optimizing throughput; The calculation expression of throughput can obtain by the data transfer model of setting up different ACK mechanism, this be one about the expression formula of Frame length, transmission rate, channel bit error rate, frame period time and ACK length parameter, under different channel bit error rates, obtain corresponding optimum frame length by the method for numerical optimization.

The calculation expression of described throughput is as follows:

Present embodiment is not considered the transmission error of Beacon frame, data frame header, ACK claim frame and ACK frame, and for Imm-ACK and Dly-ACK mechanism, the throughput expression formula is expressed as follows:

$S=\frac{L_D(1-{\mathrm{\Π}}_{k=1}^{N_{\max }+1}\mathrm{FER}\left(k\right))}{T_{\mathrm{slot}}[{\mathrm{\Σ}}_{k=1}^{N_{\max }+1}q(1-\mathrm{FER}\left(k\right)){\mathrm{\Π}}_{q=1}^{k-1}\mathrm{FER}\left(q\right)+(N_{\max }+1){\mathrm{\Π}}_{k=1}^{N_{\max }+1}\mathrm{FER}\left(k\right)]};$

Wherein FER (k) represents the detection frame error rate of Frame receiving terminal when the k time transmission, receiving terminal can merge detection to the Frame that retransmits after adopting the HARQ scheme, therefore FER (k) reduces along with the increase of k, and the length of FER (k) and Frame and the relation of the error rate are as follows: $\mathrm{FER}\left(k\right)=1-{(1-p_e\left(k\right))}^{L_D+L_F};$

When adopting Imm-ACK mechanism, T _SlotCan be expressed as: $T_{\mathrm{slot}}=\frac{L_D+L_F}{R_D}+\frac{L_A+L_H}{R_B}+2T_p+2\mathrm{SIFS};$

When adopting Dly-ACK mechanism (length of supposing Burst is K), T _SiotCan be expressed as:

$T_{\mathrm{slot}}=t_p+\mathrm{MIFS}+\frac{L_D+L_F}{R_D}+\frac{L_H}{R_B}+\frac{1}{K}({2t}_p+2\mathrm{SIFS}+\frac{L_R+L_A}{R_B});$

Wherein MIFS and SIFS are the frame period time that defines in the agreement;

For No-ACK mechanism, the throughput expression formula is as follows: $S=\frac{L_D(1-\mathrm{FER})}{t_p+\mathrm{MIFS}+\frac{L_D+L_F}{R_D}+\frac{L_H}{R_B}}.$

In order better to achieve the above object, the present invention is directed to the characteristics based on the PN network of IEEE 802.15.3 agreement, designed the structure of FEEDBACK CONTROL frame, it is to obtain by the structure of revising the Imm-ACK frame, the bit that has rationally utilized system to keep does not increase extra bit information.Selected best ACK mechanism and Frame length information have been comprised in the FEEDBACK CONTROL frame.

See also Fig. 1, in the PN network, usually by sending node CAP (Contention Access Period) stage of superframe to PNC request channels resource, be sending node and receiving node distribution transmission time slot CTA (ChannelTime Allocation) after the PNC request of receiving, this information sends Beacon by PNC when each superframe begins mode passes to the node in the network, and two nodes then carry out transfer of data in the CTA that is assigned to.In order to realize self adaptation ACK mechanism and the adjustment of Frame length, receiving node need to estimate channel conditions, thereby selects optimum ACK mechanism and corresponding optimal transmission Frame length information, and these information are fed back to sending node and PNC.For consistent with agreement, the FEEDBACK CONTROL frame that designs among the present invention is to obtain by the ACK frame structure that modification Imm-ACK mechanism adopts, and its length is the length (10 byte) of MAC Header; Frame control (Frame control) part comprises 2 bytes, comprises Framesize level, the ACK policy in order to identify optimum ACK mechanism, the type Frame type that reaches expression FEEDBACK CONTROL frame of the reserved field that utilizes in the agreement.

The concrete meaning of FEEDBACK CONTROL frame structure shown in Figure 1 is described below:

(1) about the sign of FEEDBACK CONTROL frame, according to IEEE 802.15.3 agreement, 3 bits among Fig. 1 among the Frame type represent respectively Beacon frame, Imm-ACK frame, Dly-ACK frame, command frame and Frame with 000,001,010,011 and 100 respectively, and therefore this field can be set represents the FEEDBACK CONTROL frame with 101;

(2) sign of adjusting about ACK mechanism, we in the drawings ACK policy partly represent respectively that with 00,01 and 10 No-ACK to be selected is machine-processed, Imm-ACK is machine-processed and Dly-ACK is machine-processed;

(3) sign of adjusting about Frame length information, we represent with b15-b11 part (this part is reserved field in the former agreement) among Fig. 1.Defined eight kinds of optional Frame length in the physical layer of IEEE 802.15.3 agreement: therefore 64 bytes, 256 bytes, 512 bytes, 1024 bytes, 1280 bytes, 1536 bytes, 1792 bytes, 2044 bytes can represent respectively eight kinds of above-mentioned Frame length information with three bits 000,001,010,011,100,101,110 and 111.

(4) implication of other field can be with reference to IEEE 802.15.3 agreement among Fig. 1.

Based on IEEE 802.15.3 agreement, and after combining adaptive ACK mechanism and the adjustment of Frame length the basic network framework as shown in Figure 2, the implementation flow process is as follows:

Step 1, initial ACK mechanism are assumed to be Imm-ACK mechanism, sending node is first to PNC request channels resource in the CAP stage, PNC is according to the information of request, for this communication link distributes transmission time slot CTA (having reserved the transmission time for the FEEDBACK CONTROL frame among the CTA), and by sending the information of Beacon broadcast channel assigned;

Step 2, sending node solve corresponding channel allocation information after receiving Beacon, communication link is based upon in the CTA time slot of appointment, and communication node carries out data transfer according to the ACK mechanism of appointment;

Step 3, receiving node estimating channel conditions, and according to the code modulation mode that current link adopts, select best ACK mechanism and Frame length, rear to sending node and PNC transmission FEEDBACK CONTROL frame at CTA;

Step 4, PNC are combined in the information request channel that the CAP of current superframe received in the cycle after receiving the FEEDBACK CONTROL frame, be that this communication link distributes suitable CTA length, when next superframe begins by Beacon broadcast allocation information;

Step 5, sending node upgrade the Frame length of ACK mechanism and transmission after receiving the FEEDBACK CONTROL frame, and are combined in the transmission time slot information in the Beacon frame of receiving when next superframe begins, and carry out data communication in the CTA of appointment;

Step F, circulation execution in step C are to step e.

In sum, beneficial effect of the present invention is as follows:

(1) overhead of introducing about feedback control information.At first, the length of FEEDBACK CONTROL frame only is equivalent to the length of a data frame header; Secondly, the adaptation scheme that the present invention carries is adjusted take superframe as unit, transmission primaries only in each CTA.Therefore, the redundant information introduced of this feedback mechanism is considerably less.

(2) about the applied environment of scheme.Wireless personal network based on IEEE 802.15.3 is mainly used in the home network, than the environment of outdoor mobile communication, the channel conditions impact that is brought by Doppler frequency shift etc. will be little a lot, the variation of channel is slower in general.Therefore the cycle of parameter adjustment can arrange longer (specifically length and the applied environment by superframe determines), can further reduce like this transmission of control information, thereby improve channel utilization.

At last, the range of application of present embodiment is done to illustrate: present embodiment is based on the transfer of data in the high speed wireless personal network network of IEEE 802.15.3 agreement.The technology prerequisite: the applied environment that present embodiment is based on fixed-bandwidth proposes, receiving node at first needs channel conditions is estimated, and then the machine-processed and Frame length of the ACK that selects the best, when realizing, also can try to achieve first by numerical optimization the mapping table of channel conditions (such as characterizing with bit error rate) and optimum ACK mechanism and Frame length, as long as receiving node is passed to sending node and PNC by the FEEDBACK CONTROL frame with these information again by tabling look-up to select optimized parameter.In addition, in order to guarantee the transmission reliability in the abominable situation of channel conditions, communication equipment should have the functional module that realizes HARQ.

Above embodiment is the unrestricted technical scheme of the present invention in order to explanation only.Any modification or partial replacement that does not break away from spirit and scope of the invention all should be encompassed in the middle of the claim scope of the present invention.

Claims (8)

1. method that improves utilization rate of wireless personal network channel is characterized in that: the method comprises the step of adjusting transfer of data ACK mechanism; When the error rate of channel less than or equal to 1e ^-5Shi Caiyong No-ACK mechanism, when the error rate of channel more than or equal to 1e ^-3Shi Caiyong Imm-ACK or Dly-ACK mechanism.

2. the method for described raising utilization rate of wireless personal network channel according to claim 1, it is characterized in that: described method also comprises the step of adjusting Frame length; When the error rate of channel less than 1e ^-5More than Shi Zengjia Frame length to 1536 byte, when the error rate of channel greater than 1e ^-3In time, reduce below Frame length to 512 byte.

3. the method for described raising utilization rate of wireless personal network channel according to claim 1, it is characterized in that: described private wireless network comprises some sending nodes, some receiving nodes, some PNC; Receiving node is estimated channel conditions, selects optimum ACK mechanism and corresponding optimum frame length information, and described information is fed back to corresponding sending node and PNC, and the form that described information exchange is crossed the FEEDBACK CONTROL frame sends.

4. the method for described raising utilization rate of wireless personal network channel according to claim 3 is characterized in that: the selection of described optimum ACK mechanism, and the selection of optimum frame length obtain by the calculation expression of optimizing throughput; The expression formula of throughput obtains by the data transfer model of setting up different ACK mechanism, this be one about the expression formula of Frame length, transmission rate, channel bit error rate, frame period time and ACK length parameter, under different channel bit error rates, obtain corresponding optimum frame length by the method for numerical optimization.

5. the method for described raising utilization rate of wireless personal network channel according to claim 3, it is characterized in that: described FEEDBACK CONTROL frame comprises the Frame control part of 2 bytes.

6. the method for described raising utilization rate of wireless personal network channel according to claim 5 is characterized in that: described Frame control partly comprises the Frame size level of the reserved field that utilizes in the agreement, in order to the ACK policy that represents optimum ACK mechanism, and the Frame type of expression FEEDBACK CONTROL frame type.

7. according to claim 1 to the method for the described raising utilization rate of wireless personal network channel of 6 any one, it is characterized in that: described method comprises the steps:

Steps A, initial, the ACK mechanism of transfer of data is No-ACK mechanism, Imm-ACK is machine-processed or Dly-ACK mechanism, sending node is first to PNC request channels resource in the contention access period CAP stage, PNC is according to the information of request, for this communication link distributes transmission time slot CTA, reserved the transmission time for the FEEDBACK CONTROL frame among the CTA, and by sending the information of Beacon broadcast channel assigned;

Step B, sending node solve corresponding channel allocation information after receiving Beacon, communication link is based upon in the CTA time slot of appointment, and communication node carries out data transfer according to the ACK mechanism of appointment;

Step C, receiving node estimating channel conditions, and according to the code modulation mode that current link adopts, select best ACK mechanism and Frame length, rear to sending node and PNC transmission FEEDBACK CONTROL frame at the CTA time slot;

Step D, PNC are combined in the information request channel that the CAP of current superframe received in the cycle after receiving the FEEDBACK CONTROL frame, be that this communication link distributes suitable CTA length, when next superframe begins by Beacon broadcast allocation information;

Step e, sending node upgrade the Frame length of ACK mechanism and transmission after receiving the FEEDBACK CONTROL frame, and are combined in the transmission time slot information in the Beacon frame of receiving when next superframe begins, and carry out data communication in the CTA of appointment;

Step F, circulation execution in step C are to step e.

8. according to claim 1 to the method for the described raising utilization rate of wireless personal network channel of 6 any one, it is characterized in that: when the error rate of channel greater than 1e ^-5Less than 1e ^-3Shi Caiyong No-ACK mechanism or Imm-ACK or Dly-ACK mechanism.

Images